1. Technical Field
The present invention relates to a resonator element, a resonator, an oscillator, an electronic device, and a moving object.
2. Related Art
A so-called two-legged tuning fork type quartz crystal resonator is known as a resonator (for example, refer to JP-A-2011-223229). For example, as disclosed in JP-A-2011-223229, a resonator element included in the resonator includes a base portion and two vibrating arms extending from the base portion so as to be parallel to each other, and flexurally vibrates the two vibrating arms in an in-plane direction so that the arms alternately repeat mutual approach and separation.
A resonator element according to JP-A-2011-176665 includes a notch portion formed by notching the base portion along a direction in which vibrating arms are lined up. In order to solve a problem in that stress is likely to concentrate due to a sharp wedge-shaped point formed in a distal end of the base portion of the notch portion on the center side by over-etching at the time of formation of the notch portion using wet etching, an inclination portion is provided on the opening side of the notch portion in a direction in which the vibrating arms are lined up so that the notch portion has a shape in which a width along an extension direction of the vibrating arms increases toward the opening side. Thus, over-etching is suppressed, and the sharp wedge-shaped point is not formed in the distal end, thereby increasing impact resistance.
However, according to the resonator element disclosed in JP-A-2011-176665, in an outer edge of the notch portion on the vibrating arm side when seen in a plan view, a junction between a curved line 12 and a straight line 12a has a corner portion A having a discontinuous curvature. Thus, there is a problem in that stress is likely to concentrate on the corner portion A and it is not possible to sufficiently increase impact resistance.